Disc brake

ABSTRACT

A disc brake for a two-wheeled vehicle, such as a motorcycle, is disclosed. The brake includes a torque member fastened to a nonrotative part of the vehicle, a two-piece caliper carried by the torque member, and a pair of pins carried by the caliper which slidably support a pair of friction elements adjacent opposed friction faces of a convention disc brake rotor. The torque member is rigidly secured to the pins, a sliding connection being provided between the pins and the caliper to permit the latter to slide axially with respect to the rotor. Bolts are provided to hold the pieces of the caliper together. The pins which slidably support the friction elements are bolts which also hold the two pieces of the caliper together.

BACKGROUND OF THE INVENTION

This invention relates to a disc brake for a vehicle.

Because of their inherent advantages, disc brakes are being increasingly used on all types of motor vehicles, including two-wheeled vehicles, such as motorcycles. Motorcycle disc brakes, however, are designed so that they are much smaller than passenger car disc brakes, in order to save weight and also because the smaller size brakes will provide sufficient stopping capability for a motorcycle. Furthermore, a smaller, lighter, and more simple disc brake is desirable for motorcycles in order to minimize cost.

SUMMARY OF THE INVENTION

Therefore, an important object of this invention is to design a disc brake for two-wheeled vehicles, such as motorcycles, which is less complicated than prior art disc brakes.

Another important object of this invention is to design a motorcycle disc brake which is less expensive than prior art disc brakes.

A still further object of this invention is to design a lightweight disc brake for motorcycles.

Still another object of this invention is to insure even lining wear of the friction elements.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a transverse cross-sectional view of a disc brake made pursuant to the teachings of my present invention;

FIG. 2 is a fragmentary cross-sectional view taken substantially along lines 2--2 of FIG. 1; and

FIG. 3 is a cross-sectional view taken substantially along lines 3--3 of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIGS. 1-3 of the drawings, a disc brake generally indicated by a numeral 10 includes a rotor 12 which is mounted for rotation with a member to be braked, such as the wheel of a motorcycle. The rotor 12 defines a pair of opposed friction faces 14, 16 on opposite sides thereof. A pair of friction elements 18, 20 are disposed adjacent friction faces 14 and 16 and are adapted to be urged thereagainst when a brake application is effected, whereby frictional engagement of the friction elements 18 and 20 with the friction faces 14 and 16 retard rotation of the rotor 12.

The friction elements 18, 20 are urged against the friction faces 14 and 16 by a caliper generally indicated by the numeral 22. The caliper 22 includes a pair of radially inwardly extending portions 24, 26 which extend generally parallel to the friction faces 14, 16, respectively, and which operatively engage the friction elements 18, 20. Caliper 22 further includes a bridge portion 28 which traverses the periphery of the rotor 12 and which interconnects the inwardly extending portions 24, 26. The inwardly extending portion 24 includes a conventional fluid motor assembly consisting of a piston 30 slidably received in a bore 32 which cooperates with the closed end of the bore 32 to define a variable volume chamber 34 therebetween. The chamber 34 is communicated to a source of fluid pressure, such as the vehicle master cylinder. Piston 30 also engages the friction element 18 to urge the latter against the rotor 12 when a brake application is effected. The caliper 22 is divided into two pieces, one piece consisting of the inwardly extending portion 24 and the bridge portion 28, and the other piece consisting of the inwardly extending portion 26. A pair of bores 38, 40 are defined in the inwardly extending portion 24 which register with corresponding bores 42, 44 in the inwardly extending portion 26. Opposite ends of a pin 46 are slidably received in the bores 38, 42, and are provided with seals 48, 50 which prevent contaminants from interfering with the sliding fit between the pin and the bores and which also perform a noise abatement and pin alignment function. If necessary, the cavities defined between the ends of the pins and their corresponding bores may be vented to prevent creation of a vacuum in these cavities. Bores 40 and 44 receive corresponding opposite ends of another pin 52. Consequently, the caliper 22 is able to slide axially with respect to the rotor 12 on the pins 46, 52. Friction elements 18, 20 are provided with apertures 51, 53 which slidably receive the pins 46, 52 so that the friction elements slide on the pins when a brake application is effected. After the pins are installed in the caliper, the two pieces of caliper are held together by bolts 54, 56.

Brake 10 further includes a torque member generally indicated by the numeral 58. Torque member 58 includes a mounting portion 60, which is rigidly secured to a non-rotative portion of the vehicle by bolts (not shown) extending through bolt holes 62, 64. Torque member 58 further includes a portion 66 which is disposed in the space defined between the outer circumferential surface of the rotor and the bridge portion 28 of the caliper, and a connecting portion 68 which extends through an aperture 70 provided in the bridge portion 28 and which interconnects the mounting portion 60 and the portion 66. The portion 66 includes apertures 72, 74 through which the pins 46, 52 extend. The pins are rigidly connected to the portion 66 of the torque member 58, so that the pins are restrained against relative movement with respect to the torque member.

MODE OF OPERATION OF THE PREFERRED EMBODIMENT

When a brake application is effected, fluid pressure is communicated from the vehicle's master cylinder into the variable volume chamber 34, where it acts upon the piston 30 urging the latter to the left, viewing FIG. 3. Movement of piston 30 to the left urges the friction element 18 into frictional engagement with the friction face 14. Because of the slidable connection between the pins 46, 52, and their corresponding bores 38, 42 and 40, 44, reaction forces transmitted through the bridge portion 28 acting through the inwardly extending portion 26, 16 urge friction element 20 into frictional engagement with friction face 16. It will be noted that, because of this sliding connection between the pins 46, 52 and their corresponding bore, that the caliper 22 will automatically reposition itself as the friction elements 18, 20 wear. It is for this reason that the bores 42, 44 are made substantially deeper than the ends of the pins 46, 42. As the friction elements 18, 20 wear, the pins 46, 52 will extend more deeply into their corresponding bores 42, 44, and will extend out of their corresponding bores 38, 40. 

We claim:
 1. In a disc brake for a vehicle:a rotor mounted for rotation with a member to be braked and having a pair of opposed friction faces; a pair of friction elements carried adjacent said friction faces and adapted to frictionally engage said opposed friction faces when a brake application is effected; a torque member secured to a non-rotative portion of the vehicle; a pair of pins carried by said torque member and restrained against relative movement with respect thereto, said pins being circumferentially spaced and extending axially with respect to said rotor, said friction elements being slidably mounted on said pins; a caliper carried by said torque member, said caliper having a pair of inwardly extending portions disposed adjacent said friction elements for urging the latter into braking engagement with their corresponding friction faces, said caliper further including a bridge portion traversing the periphery of said rotor and interconnecting said inwardly extending portions, and fluid motor means carried by the caliper for effecting a brake application; each of said inwardly extending portions defining corresponding bores therein located radially outwardly of said periphery of the rotor, the bores in one of said inwardly extending portions registering with corresponding bores in the other portion, said registering bores receiving opposite ends of said pins; said caliper including at least two separate pieces; and means for holding said caliper together; said means for holding said caliper together being separate from said pin means.
 2. In a disc brake for a vehicle:a rotor mounted for rotation with a member to be braked and having a pair of opposed friction faces; a pair of friction elements carried adjacent said friction faces and adapted to frictionally engage said opposed friction faces when a brake application is effected; a torque member secured to a non-rotative portion of the vehicle; a pair of pins carried by said torque member and restrained against relative movement with respect thereto said pins being circumferentially spaced and extending axially with respect to said rotor, said friction elements being slidably mounted on said pins; a caliper carried by said torque member, said caliper having a pair of inwardly extending portions disposed adjacent said friction elements for urging the latter into braking engagement with their corresponding friction faces, said caliper further including a bridge portion traversing the periphery of said rotor and interconnecting said inwardly extending portions, and fluid motor means carried by the caliper for effecting a brake application; each of said inwardly extending portions defining corresponding bores therein located radially outwardly of said periphery of the rotor, the bores in one of said inwardly extending portions registering with corresponding bores in the other portion, said registering bores receiving opposite ends of said pins; said torque member being secured to said pins and restraining them from movement with respect to the torque member; said opposite ends of said pins being slidably received in said bores whereby said caliper slides on said pins with respect to said torque member.
 3. The invention of claim 2:said torque member including a portion extending into the space between the periphery of said rotor and the bridge portion of said caliper; said extending portion of the torque member being secured to said pins.
 4. The invention of claim 1:said caliper including two separable pieces, the bores in said one inwardly extending portion of the caliper being located on one piece of the caliper and the bores in the other inwardly extending portion being located on a different piece of the caliper; means holding the caliper together including bolts extending through apertures in one of the pieces of the caliper to threadedly engage the other piece; said pins extending axially into said registering bores, which registering bores are disposed on said caliper between said bolts.
 5. The invention of claim 1:said bridge portion defining an aperture therein; said torque member including a mounting portion adapted for attachment to said non-rotative portion of the vehicle, a connecting portion extending between said mounting portion and said portion of the torque member extending into the space between the periphery of said rotor and said bridge portion of the caliper, said connecting portion of the torque member extending through said aperture.
 6. The invention of claim 5:said portion of the torque member extending into the space between the periphery of said rotor and said bridge portion of the caliper carrying said pair of pins for slidably mounting said pair of friction elements and said caliper. 